Core B: The overall goal of this Center proposal is to develop effective diagnostic, prognostic and therapeutic measures against NIAID Category A-C pathogens. In particular, we wish to establish biosignatures of human cells exposed in vitro and in vivo to Category A-C pathogens. In this context, the main purpose of this Microarray Core will be to provide Center's Investigators with expertise in microarray gene expression analysis of human cells. Our long term goal is to establish microarray analysis of blood leukocytes as a platform technology for the diagnosis of biothreat exposure and decision making with regard to therapeutics and, on a larger scale, Public Health. Microarray analysis of gene expression in cancer has already been put in clinical practice for the routine prognostic screening in patients with breast cancer. Our preliminary results demonstrate the diagnostic and prognostic value of microarray blood analysis in patients with Systemic Lupus Erythematosus, thus extending the application of this technology beyond cancer and towards immune dysfunction. Our strategy will be based on a comprehensive analysis of human cells response to different classes of pathogenic microorganisms in vitro and in vivo. This will allow identification of common molecular host biosignatures induced by different microbial infections, prompt diagnosis of exposure and identification of a class of pathogen. The goal of this Core is to provide Affymetrix based analysis of gene expression patterns of human cells exposed to Class A-C pathogens in vitro and in vivo. The objectives are: 1) To establish and distribute within the Center relevant standard operating procedures (SOP's). 2) To analyze, using Affymetrix technology and GeneSpring expression analysis software, samples obtained from Investigators of the Center. 3) To validate expression levels of candidate genes by real-time PCR. 4) To organize and maintain LIMS and Microsoft Access database system, which contains > 500 samples. 5) To be abreast with progresses in the field, most particularly technology and analysis software. The Core will provide support and expertise to virtually all Center's Investigators.